Electric machine including a shaft having a pump vane

ABSTRACT

An electric machine includes an electric machine housing having a first end, a second end, and an interior. A stator is fixedly mounted relative to the electric machine housing. A pump housing is provided at one of the first and second ends. A rotor is rotatably supported relative to the stator. The rotor includes a shaft having a first end that extends to a second end through an uninterrupted intermediate portion having an outer surface. One of the first and second ends extends into the pump housing. At least one vane element projects from the outer surface and is arranged in the pump housing.

BACKGROUND OF THE INVENTION

Exemplary embodiments pertain to the art of electric machines and, moreparticularly, to an electric machine including a shaft having a pumpvane.

Electric machines generally include a housing that encloses a rotor anda stator. The rotor typically includes a rotor hub. The rotor hubsupports a plurality of rotor windings that, when acted upon by amagnetic field generated by the stator, cause the rotor to rotate. Insome cases, the rotor will include laminations that support permanentmagnets. The permanent magnets also interact with the magnetic fieldsupplied by the stator causing the rotor to rotate. The rotor hub isjoined to a shaft that is supported by one or more bearings. In somecases, a coolant is introduced into the housing to exchange heat withthe rotor, stator and/or other internal components. Coolant may besupplied by an external pump that guides a liquid coolant into and outfrom the housing. In other cases, the electric machine may include anintegral pump that is connected to and driven by the shaft.

BRIEF DESCRIPTION OF THE INVENTION

Disclosed is an electric machine including an electric machine housinghaving a first end, a second end, and an interior. A stator is fixedlymounted relative to the electric machine housing. A pump housing isprovided at one of the first and second ends. A rotor is rotatablysupported relative to the stator. The rotor includes a shaft having afirst end that extends to a second end through an uninterruptedintermediate portion having an outer surface. One of the first andsecond ends extends into the pump housing. At least one vane elementprojects from the outer surface and is arranged in the pump housing.

Also disclosed is a method of pumping liquid in an electric machine. Themethod includes driving a rotor shaft having a first end that extends toa second end through an uninterrupted intermediate portion having anouter surface, rotating at least one vane element projecting outwardfrom the outer surface in a pump housing provided in an electric machinehousing, generating a fluid pressure in the pump housing, and urging thefluid from the pump housing.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way.With reference to the accompanying drawings, like elements are numberedalike:

FIG. 1 depicts a cross-sectional view of an electric machine including arotor having a shaft provided with at least one vane in accordance withan exemplary embodiment;

FIG. 2 depicts a partial cross-sectional view of the shaft and at leastone vane of FIG. 1;

FIG. 3 depicts a partial perspective view of a pump housing and shafthaving pump vanes in accordance with an aspect of the exemplaryembodiment; and

FIG. 4 depicts a partial perspective view of the shaft having multiplepump vanes in accordance with another aspect of the exemplaryembodiment.

DETAILED DESCRIPTION OF THE INVENTION

A detailed description of one or more embodiments of the disclosedapparatus and method are presented herein by way of exemplification andnot limitation with reference to the Figures.

An electric machine in accordance with an exemplary embodiment isindicated generally at 2 in FIG. 1. Electric machine 2 includes ahousing 4 having an annular side wall 6 that extends from a first endwall 8 to a cantilevered end 9 defining an opening 10. A second end wallor cover 12 is coupled to cantilevered end 9 and extends across opening10. Annular side wall 6, first end wall 8 and cover 12 collectivelydefine an interior portion 14. Annular side wall 6 includes an innersurface 17. At this point it should be understood that annular side wall6 may take on many geometries and should not be considered to be limitedto being circular.

Housing 4 is shown to include a liquid pump 24 coupled to first end wall8. Liquid pump 24 is configured to create a pressurized flow of liquidwithin interior portion 14. For example, liquid pump 24 may generate aflow of coolant such as oil, glycol, or the like within housing 4.Liquid pump 24 includes a pump housing 27 having an inner wall 30. Innerwall 30 defines a pump chamber 32 having a center axis 33. Inner wall 30is also shown to include an outlet 34 and an inlet 35 that fluidicallyconnects pump chamber 32 and interior portion 14. Pump housing 27includes a cover 36 that fluidically seals pump chamber 32.

Electric machine 2 is also shown to include a stator 40 arranged oninner surface 17. Stator 40 includes a body or stator core 42 thatsupports a plurality of stator windings 44 having a first end turnportion 46 and a second end turn portion 47. A rotor assembly 54 isrotatably mounted to housing 4 relative to stator 40. Rotor assembly 54includes a rotor hub 57 that supports a plurality of rotor laminations59. Rotor laminations 59 include permanent magnets (not shown). Rotorassembly 54 may alternatively be provided with a rotor core and rotorwindings. Rotor hub 57 is coupled to a rotor shaft 62. Rotor shaft 62 issupported to housing 4 through a first bearing 64 provided on first endwall 8 and a second bearing 65 provided on second end wall 12. Rotorshaft 62 includes a first end portion 68 that extends to a second endportion 69 through an uninterrupted intermediate portion 71. The term“uninterrupted” should be construed to describe a rotor shaft that ismaterially integral from the first end to the second end. “Materiallyintegral” should be understood to mean that intermediate portion 71 isdevoid of connections, couplings or the like. Rotor shaft 62 includes ashaft axis 74 that is off-set relative to center axis 33 of pump chamber32.

In accordance with an aspect of the exemplary embodiment illustrated inFIG. 2, rotor shaft 62 includes a slot 80 arranged near second endportion 69. Slot 80 is present in pump chamber 32 and is provided with avane element 83. Vane element 83 includes a vane body 86 having a firstend section 89 that extends to a second end section 90 through anuninterrupted, materially integral, intermediate portion 92. Vaneelement 83 is slidingly received in slot 80 such that upon rotation ofrotor shaft 62, one of first and second end sections 89 and 90 contactsinner wall 30 generating a flow of liquid from inlet 35 to outlet 34.

In accordance with another aspect of an exemplary embodiment illustratedin FIG. 3, rotor shaft 62 includes a first slot 110 and a second slot112. First and second slots 110 and 112 bisect and extend throughintermediate portion 71. A first vane element 115 is provided in firstslot 110 and a second vane element 118 is provided in second slot 112.First vane element 115 includes a first vane portion 122 and a secondvane portion 123 that are coupled through a biasing member 125. Biasingmember 125 urges first and second vane portions 122 and 123 outward fromrotor shaft 62 and into contact with inner wall 30. Similarly, secondvane element 118 includes a first vane portion 128 and a second vaneportion 129 coupled through a biasing member 131. In a manner similar tothat described above, biasing member 131 urges first and second vaneportions 128 and 129 outward from rotor shaft 62 and into contact withinner wall 30.

At this point it should be understood that the exemplary embodimentsdescribe an electric machine including a housing having an integralpump. The integral pump guides liquid, such as coolant into a housing.The coolant flow is generated by one or more vane elements that areprovided in a materially integral, uninterrupted shaft. It should alsobe understood that the arrangement of vane elements may vary. Inaddition to the vane elements depicted in FIGS. 2 and 3, rotor shaft 62may be provided with multiple vane elements 150-152 that are axiallyoff-set relative to one another as shown in FIG. 4. In such anarrangement, rotor shaft 62 may include multiple slots, one of which isshown at 160. A biasing member 162 may be provided in slot 160 to urgevane element 150 outward from rotor shaft 62. Biasing member 162 maytake the form of a coil spring that is inserted into rotor shaft 62through an opening 164 that registers with slot 160. A fastener, such asa set screw (not shown), may be employed to retain biasing member 162 inrotor shaft 62. Of course, still other arrangements of vanes may beemployed.

While the invention has been described with reference to an exemplaryembodiment or embodiments, it will be understood by those skilled in theart that various changes may be made and equivalents may be substitutedfor elements thereof without departing from the scope of the invention.In addition, many modifications may be made to adapt a particularsituation or material to the teachings of the invention withoutdeparting from the essential scope thereof. Therefore, it is intendedthat the invention not be limited to the particular embodiment disclosedas the best mode contemplated for carrying out this invention, but thatthe invention will include all embodiments falling within the scope ofthe claims.

What is claimed is:
 1. An electric machine comprising: an electricmachine housing having a first end, a second end and an interior; astator fixedly mounted relative to the electric machine housing; a pumphousing provided at one of the first and second ends; a rotor rotatablysupported relative to the stator, the rotor including a shaft having afirst end portion, that extends to a second end portion through anuninterrupted intermediate portion having an outer surface, one of thefirst and second ends extends into the pump housing; and at least onevane element projecting from the outer surface and arranged in the pumphousing.
 2. The electric machine according to claim 1, wherein the pumphousing includes a center axis, the rotor shaft extending into the pumphousing off-set from the center axis.
 3. The electric machine accordingto claim 1, wherein the pump housing is provided at the second end. 4.The electric machine according to claim 1, further comprising: a coverextending across the pump housing.
 5. The electric machine according toclaim 1, wherein the pump housing includes an inlet fluidically exposedto the interior of the electric machine housing.
 6. The electric machineaccording to claim 1, wherein the pump housing includes an outletfluidically exposed to the interior of the electric machine housing. 7.The electric machine according to claim 1, wherein the at least one vaneelement comprises a plurality of vane elements.
 8. The electric machineaccording to claim 1, wherein the rotor shaft includes a slot extendingthrough the intermediate portion, the at least one vane element beingarranged in the slot.
 9. The electric machine according to claim 8,wherein the at least one vane element is slidingly received in the slot.10. The electric machine according to claim 9, wherein the at least onevane element comprises a first vane element slidingly received in theslot and a second vane element slidingly received in the slot.
 11. Theelectric machine according to claim 10, further comprising: a biasingmember positioned between the first vane element and the second vaneelement.
 12. A method of pumping liquid in an electric machine, themethod comprising: driving a rotor shaft having a first end portion thatextends to a second end portion through an uninterrupted intermediateportion; rotating at least one vane element projecting outward from theuninterrupted outer surface in a pump housing provided in an electricmachine housing; generating a fluid pressure in the pump housing; andurging the fluid from the pump housing.
 13. The method of claim 12,wherein rotating the at least one vane element includes rotating therotor shaft along a shaft axis that is off-set from a central axis ofthe pump housing.
 14. The method of claim 12, wherein rotating the atleast one vane element includes rotating at least one vane element thatextends through a slot extending through the intermediate portion of therotor shaft.
 15. The method of claim 12, further comprising: sliding theat least one vane element along the slot into contact with an inner wallof the pump housing.
 16. The method of claim 15, wherein sliding the atleast one vane element along the slot includes sliding a first vaneelement along the slot and a second vane element along the slot.
 17. Themethod of claim 16, further comprising: biasing the first vane elementrelative to the second vane element.
 18. The method of claim 12, whereinrotating the at least one vane element includes rotating multiple vaneelements in the pump housing.
 19. The method of claim 12, wherein urgingfluid from the pump housing includes guiding fluid into the electricmachine housing.
 20. The method of claim 12, further comprising: passingfluid from the electric machine housing into the pump housing.